function lowerCamelCase(key) {
    var res = _lowerCamelCaseBy(key, '_')
    res = _lowerCamelCaseBy(res, ' ')
    return res
}

function _lowerCamelCaseBy(key, char) {
    const keyArr = key.split(char)
    const newKeyArr = keyArr.map((item, index) => {
        if (index === 0) return item
        return item.charAt(0).toLocaleUpperCase() + item.slice(1)
    })
    return newKeyArr.join('')
}
module.exports = { lowerCamelCase: lowerCamelCase }